The architecture of OpenDaylightZemlin described OpenDaylight as an extensible collection of technologies. "This project will focus on software and will deliver several components: an SDN controller, protocol plug-ins, applications, virtual overlay network, and the architectural and the programmatic interfaces that tie those things together."

This list is consistent with the basic premise of SDN, where the control and data planes are separated, with a central controller orchestrating the data flows of many physical or virtual switches (the latter running on generic server hardware). OpenFlow currently provides the only standardized interface supported by many switch vendors, but OpenDaylight also plans to support other standards as well as proprietary interfaces as the project evolves.

More exciting are the "northbound" REST APIs to the controller, atop which developers will be able to build new types of applications that run on the network itself for specialized security, network management, and so on. In support of this, Cisco is contributing an application framework, while Citrix is throwing in "an application controller that integrates Layer 4-7 network services for enabling application awareness and comprehensive control."

Although the embargoed OpenDaylight announcement was somewhat short on detail, a couple of quick conclusions can be drawn. One is that -- on the model of Hadoop, Linux, and OpenStack -- the future is now being hashed out in open source bits rather than standards committees. The rise in the importance of open source in the industry is simply stunning, with OpenDaylight serving as the latest confirmation.

More obviously, the amazing breadth of support for OpenDaylight signals new momentum for SDN. To carve up data center resources with the flexibility necessary for a cloud-enabled world where many tenants must coexist, the network needs to have the same software manageability as the rest of the infrastructure. OpenDaylight leaves no doubt the industry recognizes that need.

If the OpenDaylight Project can avoid getting bogged down in vendor politics, it could complete the last mile to the software defined data center in an industry-standard way that lowers costs for everyone. It could do for networking what OpenStack is doing for cloud computing.